Schroepfer, who joined Facebook in 2008 and was previously its vice president of engineering, has been more concerned with the site's infrastructure and reliability and its shift to mobile. That's a critical role, and Facebook is smart to give him a bigger title.

Schroepfer previously founded a company, CenterRun, which he sold to Sun Microsystems, and served as vice president of engineering for Mozilla, the maker of the Firefox Web browser.